Stimuli Selection and Configuration

In the Stimuli tab () of a task, you can choose to only use a subset of the stimuli, and make various changes to the way they are displayed or played.

Source

This is the basic set of stimuli, which the options below can further refine.

None: this is for tasks that do not require any stimuli.
Preceding task (copy all): all stimuli used in a task that precedes this one
Preceding task (selected only): Only use stimuli that the participant chose for a "selector" category in the Category Induction task.
stimulus_set: start from all stimuli in one of your pre-compiled sets

Trials

By default, trial-by-trial stimulus selection is automatically determined by the task's algorithm, typically this means randomly selecting from pairs of stimuli for each trial. If you want more control over the trials however, you can select upload_file_when_creating_batch. You can then create a trial file where you specify the specific stimuli to use per trial, per participant. Read more about trial file stimulus selection.

Exclude Preceding

Choose to filter out any stimuli used in the selected task(s). Note that the task must precede the current one for this to work.

(Filter) by type

Select only stimuli with the selected file extensions

(Filter) by name

Select only the stimuli with the selected names (file names)

Sample

All

This uses all stimuli to a maximum of 1000 (in which case the first 1000 are selected).

Random

This selects a random subset for each new participant.

Balanced

If this option is selected, a random subset is selected for each participant, but stimuli are preferred that been selected less often for other participants, aiming to sample all stimuli a roughly equal amount of times across participants. Participants are taken into account as soon as they have finished the preceding task (which is when the stimuli for the next task are selected), and only if they are participating in the same version of the experiment. This is a somewhat complicated algorithm so please contact us with any questions.

Order

Here you can upload a file that adapts the order of the stimuli (and will filter them to only include the ones listed). It should have the name of each stimulus on a new line. This only applies to certain tasks. We're happy to help you generate such a file.

Configuration

These are settings that affect the way a stimulus is displayed or played.

mute_video: play video stimuli with sound turned off
only_show_highlighted: image or video stimuli are hidden until the participant hovers over them with the mouse
box_text: text stimuli can be grabbed for dragging anywhere in a box around the text; if turned off the text can only be selected on the actual letters
box_text_opaque: see box_text; if selected, the box is not transparent and will hide stimuli underneath
suppress_highlight_while_dragging: stimuli will revert to their unhighlighted (text: short) version when moved
play_mode: whether sounds and videos should be played once, once from the start, or repeat-ed when selected, or all played continuous-ly regardless of which one is selected
audio_icon_style: whether sound stimuli should be represented as a circle or square
text_size: when setting the item size in the task settings, affect the size of the font or the box (as other stimuli types)
multiline_text_scale: if stimuli vary in the number of lines they span, which should change size, the font or the box. If the box is changed, than the font becomes smaller and vice-versa.